Design Of Small Size Wideband Reconfigurable Antennas

Current smart phones need to operate across various communication services with multiple functions. And with the development of the smart phone, it will be more difficult for antenna engineers to design antennas. In order to solve this problem, four reconfigurable handset antennas which with narrow-frame characteristic and can cover seven-band LTE/WWAN(GSM850/900/1800/1900/UMTS2100/LTE2300/2500) operations have been proposed.Firstly, a reconfigurable handset antenna with resonant structures has been proposed in this paper. The antenna has a compact structure with 7mm width and can cover seven-band LTE/WWAN(GSM850/900/1800/ 1900/ UMTS2100 /LTE2300/2500) operations. It is shown that loop antenna mode and an inverted F antenna(IFA) mode are controlled by the p-i-n diodes with simple bias circuits.Then, a reconfigurable handset antenna with different resonant length has been introduced.Two operating states with different frequencies are obtained by controlling the p-i-n diodes. The antenna can cover seven-band LTE/WWAN(GSM850/900/1800/1900/UMTS2100/LTE2300/ 2500) operations.Further, a reconfigurable antenna with dual invert-F antennas for seven-band LTE/WWAN operation in the mobile handset is presented. Both the two antennas are disposed at the bottom edge of the system circuit board of the handset and separated by a protruded ground. Two operating states with different frequencies are obtained by controlling the p-i-n diodes. The antenna can cover seven-band LTE/WWAN(GSM850/900/1800/1900/UMTS2100/LTE2300/ 2500) operations.Finally, a novel wideband antenna, which adopts a dual-state switchable lower band matching circuit, is proposed in this paper. It is shown that the operating states are controlled by the p-i-n diodes with simple bias circuits. Also note that, the operating bandwidth can be widened by adopting this technology. The antenna can cover eight-band LTE/WWAN(LTE700/2300/2500,GSM850/900/1800/1900/ UMTS2100) operations.